chore: removed SetHost and shifted SetDataResidency to sendgrid.go

[tiwarishubham635]

Fixes

1. Removed public SetHost() as it is not required for Go [SetDataResidency does exactly the same thing]
2. Shifted SetDataResidency() to sendgrid.go since it is specific to that only. Earlier it was in base_interface.go which means if someone creates a twilio_email request, then also they would be able to access SetDataResidency() and overrides host. But that doesn't make sense since it is specific to sendgrid only.

Checklist

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• [x] I have made a material change to the repo (functionality, testing, spelling, grammar)
• [x] I have read the Contribution Guidelines and my PR follows them
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• [x] I have added tests that prove my fix is effective or that my feature works
• [x] I have added the necessary documentation about the functionality in the appropriate .md file
• [x] I have added inline documentation to the code I modified

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